I believe you might have more than a few discs that comes with your Dell.
You might recognize few of these. For mine, I have:
-Vista 32 Reinstallation
-Device Drivers
-Bluetooth 355 + EDR
-MediaDirect Reinstallation Disc
-MS Works 8.5
-Roxio Creator & MyDvD 9.0
If you noticed you might have some word on the disc regarding about " Media " that would be probably your answer about reinstalling your mediacenter.
E1505 comes with the MediaCenter buttons, such as Play, stop, rewind, FF, and so on, which it integrated directly to Vista, that don't requires the drivers or programs; but MediaDirect button does need the program to do that.
Hope i helped.
You might want to list a little more info about your Studio 1435 too.